clk: samsung: Make of_device_id array const

Array of struct of_device_id may be be const as expected by
of_match_table field and of_find_matching_node_and_match() function.

Signed-off-by: Krzysztof Kozlowski <k.kozlowski@samsung.com>
Reviewed-by: Jingoo Han <jg1.han@samsung.com>
Signed-off-by: Tomasz Figa <t.figa@samsung.com>
diff --git a/drivers/clk/samsung/clk-exynos4.c b/drivers/clk/samsung/clk-exynos4.c
index 1563ea8..ac163d7 100644
--- a/drivers/clk/samsung/clk-exynos4.c
+++ b/drivers/clk/samsung/clk-exynos4.c
@@ -1254,7 +1254,7 @@
 
 }
 
-static struct of_device_id ext_clk_match[] __initdata = {
+static const struct of_device_id ext_clk_match[] __initconst = {
 	{ .compatible = "samsung,clock-xxti", .data = (void *)0, },
 	{ .compatible = "samsung,clock-xusbxti", .data = (void *)1, },
 	{},